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Abstract:

A straddle-type electric vehicle (e.g., electric motorcycle 1) comprising
a driving motor and an electric power control unit for controlling
electric power supplied from batteries to the driving motor, a case of
the electric power control unit is mounted to the battery box from
outward, and electrode terminals protruding outward from the case are
inserted into insertion holes of the battery box. The electrode terminals
protruding into inside of the battery box are connected to electrodes of
the batteries via electric conductors such as bus bars. In this
structure, electric connecting work between the batteries and the
electric power control unit can be easily carried out, high-voltage lines
can be minimized in length, and the high-voltage lines are not exposed to
outside.

Claims:

1. A straddle electric vehicle comprising: an electric motor for driving
the electric vehicle; an electric storage device for storing electric
power supplied to the electric motor; and an electric power controller
for controlling the electric power supplied from the electric storage
device to the electric motor; wherein a case of the electric power
controller is mounted to an accommodating box of the electric storage
device from outward; wherein the case is provided with an electrode
terminal connected to an electric circuit inside of the case such that
the electrode terminal protrudes outward from the case; and wherein a
floor portion or a side wall portion of the accommodating box has an
insertion hole into which the electrode terminal is inserted, and the
electrode terminal which is inserted into the insertion hole and
protrudes into inside of the accommodating box is connected to an
electrode of the electric storage device via an electric conductor.

2. The straddle electric vehicle according to claim 1, wherein the
accommodating box opens upward, and the floor portion of the
accommodating box has the insertion hole; wherein the case is mounted to
the floor portion of the accommodating box from below; and wherein the
electrode terminal protruding from an upper surface of the case is
inserted into the insertion hole.

3. The straddle electric vehicle according to claim 2, wherein the
accommodating box is placed in an inclined state such that the floor
portion is directed downward and obliquely forward.

4. The straddle electric vehicle according to claim 3, wherein a vehicle
body frame includes a head pipe and a main frame extending rearward from
the head pipe such that the main frame is inclined downward; wherein the
accommodating box extends along the main frame between a front wheel and
a rear wheel, and a lower surface of the floor portion of the
accommodating box protrudes obliquely forward to be lower than a lower
edge of the main frame; and wherein the case of the electric power
controller is mounted to the floor portion of the accommodating box in a
rearward location.

5. The straddle electric vehicle according to claim 1, wherein the floor
portion or the side wall portion which has the insertion hole is provided
with a frame portion extending toward a facing surface of the case which
faces the floor portion or the side wall portion such that the frame
portion surrounds the facing surface.

6. The straddle electric vehicle according to claim 1, wherein the floor
portion or the side wall portion which has the insertion hole is provided
with a swelling portion which surrounds the insertion hole and swells
inward in the accommodating box, and the insertion hole opens in a
swelling surface of the swelling portion.

7. The straddle electric vehicle according to claim 6, wherein the case
is provided with a seat portion swelling outward such that the seat
portion is placed into a recess provided at a reverse side of the
swelling portion of the accommodating box, and the electrode terminal
protrudes from the seat portion.

8. The straddle electric vehicle according to claim 1, wherein the
electric conductor is elongated and is provided to extend from a location
in the vicinity of the insertion hole of the floor portion or the side
wall portion of the accommodating box to an upper portion of the
accommodating box.

9. The straddle electric vehicle according to claim 1, wherein the
accommodating box is made of resin and supported on a vehicle body frame.

10. The straddle electric vehicle according to claim 1, wherein the case
is mounted to a rear side wall portion of the accommodating box from
rearward.

11. A mounting structure of an electric power controller in a straddle
electric vehicle comprising: an electric motor for driving the electric
vehicle; and an electric power controller for controlling electric power
supplied to the electric motor; wherein an electric storage device for
storing the electric power supplied to the electric motor is accommodated
into an accommodating box; wherein a case of the electric power
controller is mounted to the accommodating box from outward; wherein the
case is provided with an electrode terminal connected to an electric
circuit inside of the case such that the electrode terminal protrudes
outward from the case; and wherein a floor portion or a side wall portion
of the accommodating box has an insertion hole into which the electrode
terminal is inserted, and the electrode terminal which is inserted into
the insertion hole and protrudes into inside of the accommodating box is
connected to an electrode of the electric storage device via an electric
conductor.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a straddle-type electric vehicle
including an electric motorcycle incorporating an electric motor as a
driving source, an ATV (all terrain vehicle) incorporating the electric
motor as the driving source, and a hybrid electric vehicle incorporating
an engine in addition to the electric motor. Particularly, the present
invention relates to a structure for mounting the electric power
controller in the vehicle.

BACKGROUND ART

[0002] Conventionally, as an example of a mounting structure of electric
components in an electric vehicle, in an electric motorcycle disclosed in
Patent Literature 1, battery electric components such as a main relay, a
DC/DC converter, a current sensor, and a monitoring ECU, are accommodated
into a battery box accommodating a number of batteries.

[0003] By comparison, a motor controller (electric power controller) which
generates heat of a great amount is accommodated into a case separate
from the battery box and placed under a floor of the battery box so that
the motor controller is cooled by ram air. Also, the battery box is
provided with an air discharge port which faces the motor controller.

[0005] In the conventional example, high-voltage lines connecting the
batteries to the main relay, the DC/DC converter, etc., are accommodated
in the battery box, but high-voltage lines connecting the batteries to
the motor controller penetrate a bottom portion of the battery box and
are drawn to outside of the battery box. This causes a need for many
wiring members. Therefore, there is room for reduction of a loss caused
by electric resistance.

[0006] Since the high-voltage lines connecting the batteries to the motor
controller are exposed to outside of the battery box, it is necessary to
cover the exposed high-voltage lines with a cover, or the like so that a
user of the vehicle does not touch them inadvertently. Therefore,
connecting/wiring work tends to become messy.

[0007] An object of the present invention is to provide a straddle-type
electric vehicle which can reduce, as much as possible, a length of
high-voltage lines connecting an electric storage device to an electric
power controller, eliminate a need for a cover or the like for covering
high-voltage lines by placing the high-voltage lines such that they are
not exposed, and make it easier to perform wiring work of the
high-voltage lines.

Solution to Problem

[0008] To achieve the above stated objective, a straddle-type electric
vehicle of the present invention comprises an electric motor for driving
the electric vehicle; an electric storage device for storing electric
power supplied to the electric motor; and an electric power controller
for controlling the electric power supplied from the electric storage
device to the electric motor; wherein a case of the electric power
controller is mounted to an accommodating box of the electric storage
device from outward; wherein the case is provided with an electrode
terminal connected to an electric circuit inside of the case such that
the electrode terminal protrudes outward from the case; and wherein a
floor portion or a side wall portion of the accommodating box has an
insertion hole into which the electrode terminal of the case is inserted,
and the electrode terminal which is inserted into the insertion hole and
protrudes into inside of the accommodating box is connected to an
electrode of the electric storage device via an electric conductor.

[0009] In accordance with this configuration, in a state in which the
electric power controller is mounted to the accommodating box of the
electric storage device from outward, the electrode terminal protruding
from the case of the electric power controller is inserted into the
insertion hole of the floor portion or the side wall portion of the
accommodating box and protrudes inside of the accommodating box.
Therefore, the electrode terminal has only to be connected to the
electric conductor. Since the electric conductor and the electrode
terminal which are applied with a high voltage are present inside of the
accommodating box and are not exposed to outside, there is no need for a
cover covering the electric conductor and the electrode terminal, and the
high-voltage line can be minimized in length.

[0010] Preferably, the accommodating box may open upward, and the floor
portion of the accommodating box may have the insertion hole. The case
may be mounted to the floor portion of the accommodating box from below.
Thus, since the electrode terminal protrudes upward into inside of the
accommodating box of a relatively great size, through the insertion hole
of the floor portion, a worker can insert hands into the accommodating
box through the opening of the accommodating box from above and easily
connect the electrode terminal and the electric conductor to each other
with an easy posture while seeing the electrode terminal and the electric
conductor before the electric storage device is accommodated into the
accommodating box.

[0011] The accommodating box may be placed in an inclined state such that
the floor portion is directed downward and obliquely forward. Thus, the
case of the electric power controller which is mounted to the floor
portion from below can be cooled efficiently by ram air. Alternatively, a
rear side wall portion of the accommodating box may be provided with the
insertion hole instead of the floor portion of the accommodating box, and
the case of the electric power controller may be mounted to the rear side
wall portion of the accommodating box from rearward. This has an
advantage that bouncing stones are likely to contact the case.

[0012] For example, like a motorcycle, when a vehicle body frame includes
a head pipe and a main frame extending rearward from the head pipe such
that the main frame is inclined downward, the accommodating box may
extend along the main frame between a front wheel and a rear wheel, and a
lower surface of the floor portion of the accommodating box may protrude
obliquely forward to be lower than a lower edge of the main frame, and
the case of the electric power controller may be mounted to the lower
surface of the floor portion of the accommodating box. Thus, the case can
be cooled more effectively by the air. In addition, when the case of the
electric power controller is mounted to the floor portion of the
accommodating box in a location which is rearward and relatively lower, a
user is less likely to contact the case.

[0013] Preferably, the floor portion or the side wall portion of the
accommodating box which has the insertion hole as described above may be
provided with a frame portion extending toward a facing surface of the
case which faces the floor portion or the side wall portion such that the
frame portion surrounds the facing surface. Since the frame portion
provided on the floor portion or the side wall portion of the
accommodating box surrounds the facing surface of the case, it becomes
possible to effectively prevent entry of rain water, mud, etc., into the
case.

[0014] The facing surface of the case of the electric power controller may
be provided with a joint surface which is joined to the floor portion or
the side wall portion of the accommodating box such that the joint
surface surrounds at least the electrode terminal. Thus, since the
electrode terminal is isolated from surroundings in the joint surface of
the accommodating box and the joint surface of the case, it becomes
possible to prevent entry of rain water, mud, etc.

[0015] For example, an entire or a portion of the facing surface of the
case of the electric power controller may be provided with a flat joint
surface, and the electrode terminal may protrude from the flat joint
surface. Or, a stepped surface which is lower may be provided in an
inward region surrounded by the flat joint surface, and the electrode
terminal may protrude from the stepped surface. In the same manner, the
floor portion or the side wall portion of the accommodating box may be
provided with a flat joint surface and a stepped surface surrounded by
the joint surface, and the insertion hole may open in the stepped
surface. Because of the stepped surface, water which may enter a
clearance between the joint surfaces is less likely to contact the
electrode terminal.

[0016] Preferably, the floor portion or the side wall portion of the
accommodating box which has the insertion hole as described above may be
provided with a swelling portion which surrounds the insertion hole and
swells inward in the accommodating box, and the insertion hole may open
in a swelling surface of the swelling portion. In this configuration, if
rain water enters inside of the accommodating box or water droplets are
generated inside of the accommodating box, a possibility that this water
will reach the swelling surface along the floor surface or the wall
surface of the accommodating box is low. Therefore, the water is less
likely to contact the electrode terminal.

[0017] When the floor portion or the side wall portion of the
accommodating box is provided with the swelling portion, a recess is
provided on its reverse side. Therefore, the case may be provided with a
seat portion swelling outward from the case such that the seat portion is
placed into the recess, and the electrode terminal may protrude from the
seat portion. Thus, even when the water enters the clearance between the
accommodating box and the case of the electric power controller, it is
less likely to reach the swelling surface of the seat portion, and hence
is less likely to contact the electrode terminal.

[0018] As preferable constituents inside of the accommodating box, the
electric conductor may be elongated and may be provided to extend from a
location in the vicinity of the insertion hole of the floor portion or
the side wall portion of the accommodating box to an upper portion of the
accommodating box. Thus, one end portion of the electric conductor is
connected to the electrode terminal protruding into inside of the
accommodating box through the insertion hole of the floor portion or the
side wall portion of the accommodating box as described above, then the
electric storage device is accommodated into the accommodating box, and
in this state, the electrode of the electric storage device is easily
connected to the other end portion of the electric conductor. To this
end, preferably, the other end portion of the electric conductor is
extended to a location as high as the electrode at an upper portion of
the electric storage device along the side wall of the accommodating box,
for example.

[0019] The accommodating box may be made of resin and supported on a
vehicle body frame, and the case of the electric power controller may be
supported on the accommodating box. Because of the presence of the
accommodating box made of resin, a noise-proof property of the case of
the electric power controller can be expected. More preferably, the
accommodating box is supported on the vehicle body frame via a
vibration-proof mount.

[0020] According to another aspect of the present invention, in a mounting
structure of an electric power controller in a straddle-type electric
vehicle comprising an electric motor for driving the electric vehicle;
and an electric power controller for controlling electric power supplied
to the electric motor, when an electric storage device for storing the
electric power supplied to the electric motor is accommodated into an
accommodating box, a case of the electric power controller is mounted to
the accommodating box of the electric storage device from outward.
Specifically, the case of the electric power controller is provided with
an electrode terminal connected to an electric circuit inside of the case
such that the electrode terminal protrudes outward from the case, while a
floor portion or a side wall portion of the accommodating box has an
insertion hole into which the electrode terminal is inserted, and the
electrode terminal which is inserted into an insertion hole and protrudes
into inside of the accommodating box is connected to the electrode of the
electric storage device via an electric conductor.

Advantageous Effects of Invention

[0021] In accordance with the present invention, in the straddle-type
electric vehicle in which the electric motor for driving the electric
vehicle or the electric power controller tends to be exposed to outside,
the case of the electric power controller is mounted to the accommodating
box of the electric storage device, and connected thereto in a mounting
location. Therefore, the work for connecting the case to the
accommodating box can be easily carried out. In addition, since the
length of the high-voltage line can be reduced as much as possible, and
is not exposed to outside, there is no need for a cover, etc., for
covering the high-voltage line.

BRIEF DESCRIPTION OF DRAWINGS

[0022]FIG. 1 is a right side view showing major components in an electric
motorcycle according to an embodiment of the present invention.

[0023]FIG. 2 is a perspective view showing a structure of a battery box.

[0024]FIG. 3 is an enlarged view showing a connecting structure of an
electrode terminal.

[0025]FIG. 4A is a view showing a modified example of the connecting
structure, corresponding to FIG. 3.

[0026]FIG. 4B is a view showing another modified example of the
connecting structure, corresponding to FIG. 3.

[0027]FIG. 5 is a perspective view of a structure for mounting a cooler
to an electric power control unit.

[0028]FIG. 6 is a cross-sectional view showing a cooling structure of the
electric power control unit.

[0029] FIG. 7 is a view showing a modified example of the cooling
structure, corresponding to FIG. 6.

DESCRIPTION OF EMBODIMENTS

[0030] Hereinafter, an electric motorcycle according to an embodiment of
the present invention will be described with reference to the drawings.
The stated directions recited below are from the perspective of a driver
straddling the electric motorcycle.

[0031] Schematic Configuration of Electric Motorcycle

[0032]FIG. 1 is a right side view schematically showing major components
such as a vehicle body frame, a power plant, and wheels, in an electric
motorcycle 1 (electric vehicle) according to an embodiment of the present
invention. As shown in FIG. 1, the electric motorcycle 1 includes a front
wheel 2 which is a steering wheel and a rear wheel 3 which is a drive
wheel. The front wheel 2 is rotatably mounted to lower end portions of a
pair of right and left front forks 4 extending substantially vertically.
Upper portions of the front forks 4 are mounted to a steering shaft (not
shown) via a pair of upper and lower brackets.

[0033] The steering shaft is rotatably supported in a state in which the
steering shaft is inserted into a head pipe 5 mounted to a vehicle body,
and constitutes a steering axis. A handle 6 extending in a rightward and
leftward direction is attached to the upper bracket. When the driver
manipulates the handle 6, the front forks 4 and the front wheel 2 can be
steered around the steering shaft. The handle 6 is provided at a right
end with an accelerator grip 7 which is gripped by the driver's right
hand and rotated by twisting the driver's wrist.

[0034] The vehicle body frame of the electric motorcycle 1 includes a main
frame 8 extending rearward from the head pipe 5 such that the main frame
8 is inclined slightly downward. For example, the main frame 8 is divided
into two parts, i.e., right and left parts, at a front end portion
thereof welded to the head pipe 5. The right and left parts are each
composed of pipe members 80 arranged at upper and lower sides. The pipe
members 80 extend rearward from the head pipe 5, extend rightward and
leftward, are curved inward, and then extend rearward such that the pipe
members 80 corresponding to the right part are apart from the pipe
members 80 corresponding to the left part. Then, the pipe members 80 are
curved inward and then rear end portions thereof are coupled to a pivot
frame 9.

[0035] The pivot frame 9 has a substantially rectangular frame shape. The
rear end portions of the pipe members 80 of the main frame 8 are joined
and welded to right and left side plates of the pivot frame 9 from
inward. Front end portions of a swing arm 10 supporting the rear wheel 3
are mounted between the right and left side plates of the pivot frame 9
such that the swing arm 10 is vertically pivotable. The swing arm 10
extends rearward from its pivot such that it is inclined slightly
downward. The rear wheel 3 is rotatably mounted to rear end portions of
the swing arm 10.

[0036] A rear frame 11 extends from the rear portions of the main frame 8
and upper end portions of the pivot frame 9 such that the rear frame 11
is inclined upward in a rearward direction. A straddle seat 13 is mounted
over the rear frame 11. A knee grip cover 15 is disposed in front of the
seat 13. The driver straddling the electric motorcycle 1 grips the knee
grip cover 15 between the driver's knees. By gripping the knee grip cover
15 with the driver's knees, the driver feels unity with the electric
motorcycle 1.

[0037] A battery box 20 (accommodating box of electric storage device)
accommodating batteries 21 which are the electric storage device, is
disposed such that the battery box 20 is covered with the knee grip cover
15 from above. For example, the battery box 20 is surrounded by the four
pipe members 80 of the main frame 8 from right and from left. Right and
left side wall portions of the battery box 20 are fastened to the pipe
members 80, respectively, by bolts, or the like.

[0038] As will be described in detail later, in the present embodiment,
the batteries 21 are accommodated into the battery box 20 such that the
batteries 21 are separated into right and left modules, and a ram air
path is formed between the right and left modules. An air guide duct 22
is integrally provided on a front wall of the battery box 20 to guide the
ram air from forward into the battery box 20 during driving of the
electric motorcycle 1, while an air discharge duct 23 is integrally
provided on a rear wall of the battery box 20.

[0039] For example, a front portion of the air guide duct 22 extends
forward farther than the head pipe 5. The ram air taken in through the
air guide duct 22 is guided to inside of the battery box 20, flows
through a space between the right and left modules of the batteries 20,
and is discharged through the air discharge duct 23. The air discharge
duct 23 extends rearward through a space below the seat 13. The air is
discharged smoothly rearward relative to the electric motorcycle 1
through the air discharge duct 23.

[0040] When viewed from a side as shown in FIG. 1, the battery box 20 is
provided in a location close to a center of a vehicle body in a range
from the head pipe 5 to the pivot frame 9 in the electric motorcycle 1,
and extends along the main frame 8. That is, the battery box 20 having a
great weight is mounted in the vicinity of a roll axis, which is
preferable to enhance the motion performance of the electric motorcycle
1. A lower surface of the battery box 20 protrudes obliquely forward to
be lower than a lower edge of the main frame 8, i.e., the lower pipe
member 80, and is inclined to be gradually lower in a direction from its
front edge to its rear edge.

[0041] In close proximity to and below a rear edge of the lower surface
which is the lowest location of the inclined battery box 20, a motor unit
50 including a driving motor 30 constituted by an electric motor and a
transmission 40 (power transmission mechanism) is disposed. A rear
portion of the motor unit 50 is an accommodating section of the
transmission 40. Right and left portions of the accommodating section of
the transmission 40 are fastened to and supported by the right and left
side plates of the pivot frame 9. By comparison, a front portion of the
motor unit 50 is an accommodating section of the driving motor 30. Right
and left portions of the accommodating section of the driving motor 30
are supported by hanger brackets 81 extending downward from the front
portion of the main frame 8.

[0042] An electric power control unit 60 (electric power controller) is
disposed on the lower surface of the battery box 20 in close proximity to
and above the motor unit 50. As will be described later with reference to
FIG. 6, the electric power control unit 60 is configured in such a manner
that a power module 61 incorporating a power semiconductor such as an
IGBT (insulated-gate bipolar transistor) is accommodated into a case 62.
The electric power control unit 60 is mounted to a portion of the lower
surface of the battery box 20, which portion is in a range from its
center to its front portion and directly receives the ram air flowing
through a space between the right and left hanger brackets 81.

[0043] A protective net 82 (protective member) is attached over upper
portions of the right and left hanger brackets 81 such that the
protective net 82 covers a forward side, right and left sides, and an
underside of the electric power control unit 60. The protective net 82 is
formed of, for example, a metal net, a punching metal, etc., and has
meshes which inhibit bouncing stones from passing therethrough, while
allowing the ram air to pass therethrough.

[0044] An oil cooler 70 is mounted to lower portions of the right and left
hanger brackets 81. As will be described later, a cooler 66 is
incorporated into the electric power control unit 60. Oil is cooled by
the oil cooler 70 and then is fed to the cooler 66 through an upper hose
72 (oil feeding line) to cool the power module 61. After that, the oil
flows downward through a return hose 73 (oil return line) and is returned
to the motor unit 50.

[0045] Although not described in detail, in the present embodiment, a case
of the motor unit 50 of the present embodiment is provided with an oil
pan 51 which stores oil used for lubricating and cooling the driving
motor 30 and the transmission 40, and an oil pump 52 for suctioning up
the oil from the oil pan 51. The oil discharged from the oil pump 52 is
fed with pressure to the oil cooler 70 via a lower hose 71 (oil feeding
line). A portion of the oil discharged from the oil pump 52 is fed to the
bearings of the driving motor 30, clutches and gear trains of the
transmission 30, to lubricate and cool them.

[0046] In the present embodiment, the driving motor 30 is a
motor/generator which is capable of a motor operation and a power
generation operation. The driving motor 30 operates as a motor by the
electric power supplied from the batteries 21 via the electric power
control unit 60, and outputs driving power to the rear wheel 3. By
comparison, during regenerative braking of the electric motorcycle 1, the
driving motor 30 operates as a generator to generate AC power. The AC
power is converted into DC power by an inverter of the electric power
control unit 60 and is stored in the batteries 21. Control for the
operation of the driving motor 30 and control for charge and discharge of
the batteries 20 are executed by a known method.

[0047] Mounting Structure of Batteries

[0048] In the present embodiment, to isolate high-voltage lines from the
driver and protect them from rain water or the like, the batteries 21 are
accommodated into the battery box 20 made of a resin. FIG. 2 shows a
state in which the battery box 20 is detached from the main frame 8 and
illustrated as a single unit. As shown in FIG. 2, the battery box 20 is a
rectangular casing which opens upward and has a shape in which its width
in a rightward and leftward direction is greater than its height, and a
length in a forward and leftward direction is great. Right and left side
wall portions 24 of the battery box 20 are integrally provided with
receiving seat portions 24a of bolts to mount the side wall portions 24
of the battery box 20 to the pipe members 80 of the main frame 8. Nuts
(not shown) are embedded into the receiving seat portions 24a,
respectively.

[0049] A front wall portion 25 of the battery box 20 has a circular hole
25a in a substantially center portion in a vertical direction and in the
rightward and leftward direction. The air guide duct 22 (see FIG. 1)
extends forward from a peripheral portion of the circular hole 25a. An
upper portion of the rear wall portion 26 of the battery box 20 has a
circular hole 26a in a center portion in the rightward and leftward
direction. The air discharge duct 23 (see FIG. 1) extends rearward from a
peripheral portion of the circular hole 26a. A floor portion 27 connects
lower ends of the right and left side wall portions 24, a lower end of
the front wall portion 25 and a lower end of the rear wall portion 26 has
a substantially rectangular shape. Bus bars 28 are provided to extend
from an upper surface of the floor portion 27 to an inner surface of the
rear wall portion 26.

[0050] As should be well known, the bus bars 28 are formed by molding
alloy of copper or aluminum in an elongated band shape. Each of the bus
bars 28 is an electric conductor in which it has connecting portions by
which the bus bar 28 is connected to electrode terminals, in
predetermined locations such as both end portions thereof, and a portion
other than the connecting portions is coated with an insulating material.
As will be described with reference to FIG. 3, the floor portion 27 of
the battery box 20 has insertion holes 27a into which the electrode
terminals 63 of the electric power control unit 60 are inserted.
Connecting portions 28a having circular holes connected to the insertion
holes 27a, respectively, are provided at one end portion of the bus bars
28.

[0051] Although only one module is shown in FIG. 2, for example, six
batteries 21 are accommodated into the battery box 20 in a state in which
the right module composed of the three batteries 21 and the left module
composed of the three batteries 21 are separately placed. Each module is
constructed as a detachably attachable module, in which the two
rectangular batteries 21 are arranged in the forward and rearward
direction of the electric motorcycle 1 and one module is placed on and
above the two batteries 21 and integrally coupled to the two batteries 21
by stays 29 and the like. Positive and negative electrodes 21a are
provided for each of the batteries 21 on a side surface (right side
surface shown at a near side in FIG. 2 in the case of the left module in
FIG. 2), which surface faces inside of a vehicle body during storage, and
are connected to each other by the bus bar 21b.

[0052] The three batteries 21 are connected in series. A negative terminal
of the battery 21 at an upper side which is lowest in electric potential
is connected to a relay (not shown) via the bus bar 21b. A positive
terminal of the battery 21 at a rear side of a lower side which is
highest in electric potential, is connected to the bus bar 28 of the
battery box 20 via, for example, an electric wire 21c, and connected to
an electrode terminal 63 of the electric power control unit 60 via the
bus bar 28. That is, the other end side of the bus bar 28 provided to
extend over a range from the floor portion 27 of the battery box 20 to
the rear wall portion 26 as described above, is raised up along the inner
surface of the rear wall portion 26. The connecting portion 28b at the
upper end is located in the vicinity of the opening of the battery box
20. The connecting portion 28b at the upper end is connected to the
negative terminal of the battery 21 at the upper side by an electric wire
21c.

[0053] The right battery module is configured like the left battery
module, although this will not be described in detail. The three
batteries 21 are integrally coupled to each other and electrically
connected in series. A positive terminal of the battery 21 at an upper
side which is highest in electric potential is connected to a relay,
while a negative terminal of the battery 21 at a rear side of a lower
side which is lowest in electric potential is connected to the electrode
terminal 63 of the electric power control unit 60 via the bus bar 28.
That is, in this example, the right and left battery modules are
connected in series via the relay, and a voltage of each module is set to
about a half of a high voltage required to drive the electric motorcycle
1.

[0054] In a state in which the three batteries 21 corresponding to the
left module and the three batteries 21 corresponding to the right module
are accommodated into the battery accommodating box 20, there is a gap
which becomes a passage of the ram air between the right and left
modules. Since the electrodes 21a and the bus bars 21b connecting them
are placed on the inner side surfaces of the batteries 21 facing this
gap, they are directly exposed to the ram air and thereby effectively
cooled.

[0055] Mounting Structure of Electric Power Control Unit

[0056] As described above, in the present embodiment, the electric power
control unit 60 is mounted to the battery box 20 from below. Since the
battery box 20 made of a resin intervenes between the main frame 8 and
the electric power control unit 60, the electric power control unit 60
can be supported in a vibration-proof manner, as compared to a case where
the electric power control unit 60 is directly supported on the vehicle
body frame such as the main frame 8, the pivot frame 9, and the like. In
addition, as will be described below, the case 62 of the electric power
control unit 60 is joined to the floor portion 27 of the battery box 20
from below, and thus, the high-voltage line of the battery box 20 is
connected to the high-voltage line of the electric power control unit 60
in a state in which they are isolated from their surroundings.

[0057] As schematically shown in FIG. 2, the case 62 of the electric power
control unit 60 has a flat rectangular shape. A pair of positive and
negative electrode terminals 63 connected to the power module 61
accommodated into the case 62 protrudes upward from an upper wall portion
64 of the case 62. The floor portion 27 of the battery box 20 has the
insertion holes 27a formed by the pair of circular holes such that the
insertion holes 27a penetrate the floor portion 27 and correspond to the
pair of electrode terminals 63, respectively. As shown in FIG. 3 in an
enlarged manner, the electrode terminals 63 inserted into the insertion
holes 27a from below protrude upward from the floor portion 27 of the
battery box 20 and are connected to the connecting portions 28a of the
bus bars 28, respectively.

[0058] More specifically, protruding portions 64a protruding substantially
horizontally in the forward and rearward direction are provided at four
corners of the upper wall portion 64 of the case 62 of the electric power
control unit 60. The protruding portions 64a have through holes into
which bolts are inserted to fasten the case 62 to the floor portion 27 of
the battery box 20. The upper wall portion 64 of the case 62 has a flat
surface 64b (joint surface) at one side (forward side in a state in which
the case 62 is built into the electric motorcycle 1) in a lengthwise
direction. The flat surface 64b is joined to the flat lower surface of
the floor portion 27 of the battery box 20.

[0059] In addition, in the example illustrated, rectangular seat portions
64c swelling upward are provided on relatively inward regions (inward
regions surrounded by the joint surface) of the flat surface 64b of the
upper wall portion 64 of the case 62. The electrode terminals 63 protrude
from upper surfaces of the seat portions 64c, respectively. As shown in
FIG. 3 in an enlarged manner, the floor portion 27 of the battery box 20
has swelling portions 27b swelling upward to surround the insertion holes
27a, and recesses 27c are formed on reverse surfaces of the swelling
portions 27b to contain the seat portions 64c, respectively.

[0060] The case 62 of the electric power control unit 60 is mounted to the
floor portion 27 of the battery box 20 from below. The case 62 is
fastened to the floor portion 27 of the battery box 20 by bolts
penetrating the protruding portions 64a at four corners of the upper wall
portion 64, respectively. Thereby, as shown in FIG. 3, the electrode
terminals 63 are inserted into the insertion holes 27a of the floor
portion 27 of the battery box 20, respectively, from below, and the seat
portions 64c of the upper wall portion 64 of the case 62 are placed into
the recesses 27c of the floor portion 27, respectively. The lower surface
of the floor portion 27 and the flat surface 64b of the upper wall
portion 64 of the case 62 are joined together so as to surround the seat
portions 64c.

[0061] That is, the electrode terminals 63 applied with high voltages are
surrounded by the joint surface of the battery box 20 and the joint
surface of the case 62 and thereby are isolated from the surroundings.
Thereby, high safety is achieved. In addition, rain water, mud, and the
like are less likely to enter the joint surface of the battery box 20 and
the joint surface of the case 62. If a little rain water or the like
enters a clearance between the joint surfaces, it is less likely to reach
upper surfaces of the seat portions 64c which are higher than the joint
surfaces. Therefore, the rain water or the like having entered the
clearance between the joint surfaces is less likely to contact the
electrode terminals 63.

[0062] The electrode terminals 63 are inserted into the insertion holes
27a, respectively, from below, as described above, penetrate the
connecting portions 28a of the bus bars 28 surrounding the insertion
holes 27a, and protrude upward, respectively. Male threads are formed on
outer peripheries of the electrode terminals 63, respectively. Nuts 65
threadingly engaged with the male threads tighten the connecting portions
28a of the corresponding bus bars 28, respectively. If the rain water and
the like enter the battery box 20, or water droplets stay in the floor
portion 27 of the battery box 20, the water is less likely to contact the
electrode terminals 63 and the connecting portions 28a of the bus bars 28
which are located above the upper surfaces (swelling surfaces) of the
swelling portions 27b.

[0063] Therefore, in accordance with the structure for mounting the
electric power control unit 60 to the battery box 20 as described above,
the electrode terminals 63 protruding from the case 62 of the electric
power control unit 60 are inserted into the insertion holes 27a of the
floor portion 27 of the battery box 20 and are connected to the bus bars
28 attached inside thereof. Therefore, the high-voltage lines between the
batteries 21 and the power module 61 are minimized in length, and not
exposed to outside, which eliminates a need for a cover or the like
covering the high-voltage lines.

[0064] The insertion holes 27a are formed in the floor portion 27 of the
battery box 20 which opens upward, and the electrode terminals 63 of the
electric power control unit 60 mounted to the floor portion 27 of the
battery box 20 from below protrude upward. Therefore, before the
batteries 21 are accommodated into the battery box 20, an operator can
carry out a connecting work in an easy attitude with the operator's hands
inserted into the battery box 20 from above, while seeing an interior of
the battery box 20 from above and visually checking the electrode
terminals 63 and the connecting portions 28a of the bus bars 28.

[0065] In addition to the above described configuration in which the
electrode terminals 63 of the electric power control unit 60 protrude
upward from the flat surface 64b of the upper wall portion 64 of the case
62, for example, as shown in FIG. 4A, there may be provided a stepped
surface 64d in an inward region of the flat surface 64b of the upper wall
surface 64 such that the stepped surface 64d is surrounded by the flat
surface 64b, and the electrode terminals 63 may protrude from the stepped
surface 64d. Although in the illustrated example, the seat portions 64c
are provided on the stepped surface 64d and the electrode terminals 63
protrude from the upper surfaces of the seat portions 64c, the seat
portions 64c may be omitted. By providing the stepped surface 64d in this
way, rain water or the like which has entered the clearance between the
joint surface of the floor portion 27 of the battery box 20 and the joint
surface of the upper wall portion 64 of the case 62 is less likely to
contact the electrode terminals 63.

[0066] For example, as shown in FIG. 4B, boss portions 27d protruding
downward from the floor portion 27 of the battery box 20 may be provided
to face the seat portions 64c of the case 62, and the seat portions 64c
may be butted with the boss portions 27d from below, respectively. In
this case, the floor portion 27 of the battery box 20 may be provided
with a frame portion 27e extending toward the upper wall portion 64 of
the case 62 of the electric power controller 60 which faces the floor
portion 27 below the floor portion 27 such that the frame portion 27e
surrounds its upper surface (facing surface).

[0067] As shown in FIG. 4B, the frame portion 27e has a rectangular frame
shape which is slightly greater in size than the upper wall portion 64 of
the case 62, and extends downward from the floor portion 27 of the
battery box 20 such that its lower edge is located below the upper
surface of the upper wall portion 64. The frame portion 27e can
effectively prevent entry of rain water, mud, etc., into a space between
the battery box 20 and the case 62.

[0068] Structure for Cooling Electric Power Control Unit

[0069] Next, the structure for cooling the electric power control unit 60
mounted to the battery box 20 as described above will be described with
reference to FIGS. 5 and 6. FIG. 5 is a perspective view of a structure
for mounting the cooler 66 as a separate component to the electric power
control unit 60. FIG. 6 is a cross-sectional view showing the structure
for cooling the power module 61 by the cooler 66.

[0070] As described above with reference to FIG. 2, the case 62 of the
electric power control unit 60 has a flat rectangular shape, as a whole.
The flat surface 64b to be joined to the floor portion 27 of the battery
box 20 is provided at one side (rearward side in a state in which the
case 62 is mounted in the electric motorcycle 1, hereinafter, the terms
"forward side" and "rearward side" are simply used) in a lengthwise
direction of the upper wall portion 64. As shown in FIG. 5, at the
rearward side of the flat surface 64b, there is provided a fitting
portion 62a having a rectangular cross-section which is recessed from an
upper surface to a right side surface. The cooler 66 is fitted into the
fitting portion 62a.

[0071] As described above, the lower surface of the battery box 20
protrudes obliquely forward to be lower than the lower pipe member 80 of
the main frame 8. Therefore, the electric power control unit 60 mounted
to the lower surface of the battery box 20 directly receives the ram air
from forward and thereby is cooled efficiently. In addition to this, in
the present embodiment, the power module 61 which generates heat of a
great amount is cooled by the dedicated cooler 66.

[0072] As shown in FIG. 5, a bottom of the fitting portion 62a opens
inside the case 62 of the electric power control unit 60. The cooler 66
is mounted to close the opening 62b from outward. As shown in FIG. 6, the
power module 61 is disposed inside of the case 62 so as to close the
opening 62b from inward. A lower wall (i.e., lower wall 67c of a casing
67 of the cooler 66) is in contact with a substrate 61a of the power
module 61 from above. A heat radiation grease having a high electric
conductivity is applied between the lower wall of the cooler 66 and the
substrate 61a.

[0073] As shown in FIG. 6, a power semiconductor chip 61b such as an IGBT
is mounted to the substrate 61a of the power module 61, and faces the
opening 62b of the case 62 of the electric power control unit 60 such
that its reverse surface is directed upward. In a state in which the
cooler 66 mounted so as to close the opening 62b from above is in contact
with the substrate 61a of the power module 61, heat exchange occurs
between the substrate 61a and oil flowing through a passage 67a (cooling
jacket) inside of the cooler 66.

[0074] As shown in FIG. 5, the cooler 66 includes a casing 67 which is
substantially equal in size to the fitting portion 62a of the case 62 of
the electric power control unit 60, and a lid member 68 of a rectangular
plate shape which closes an upper opening of the casing 67. The casing 67
and the lid member 68 are manufactured by molding, for example, aluminum
alloy. A flange 67b is provided along a front edge, a rear edge, and a
left edge of an upper portion of the casing 67. The flange 67b is
internally fitted to a stepped portion 62c formed along a front edge, a
rear edge and a left edge of the fitting portion 62a of the case 62 of
the electric power control unit 60, and fastened to it by screws, or the
like, (not shown).

[0075] Since the cooler 66 is detachably attached to the case 62, for
example, only the cooler 66 is detached from the case 62 during the
maintenance, or the substrate 61a of the power module 61 with the cooler
66 attached to the case 62 can be detached. Thus, maintenance can be
carried out easily. In a case where a desired cooling capability changes
depending on the weight of the electric motorcycle 1, the size of the
driving motor 30, etc., a desired and sufficient cooling capability can
be ensured merely by changing the cooler 66 while using the same case 62.

[0076] The casing 67 of the cooler 66 is provided with the passage 67a
through which cooling oil flows. The passage 67a extends from a right
front corner of the casing 67 toward a left end, then turns back at the
left end, then extends toward a right end, then turns back at the right
end, and then extends toward the left end again. Thus, the passage 67a
has a labyrinth structure which guides the oil in a rearward direction
while turning back the flow of the oil at the right end and at the left
end. Since the flow of the oil is turned back in this way, separation of
a boundary layer of the oil from a passage wall surface can be
facilitated, which improves efficiency of heat exchange by the cooler 66.

[0077] Pipe members 69 are provided to penetrate a forward portion and a
rearward portion of a right side wall of the casing 67 so as to
correspond to an inlet and an outlet of the passage 67a, respectively. As
the oil as the coolant, lubricating oil of the motor unit 50 is used. As
can be seen from FIG. 1, the upper hose 72 is coupled to the forward pipe
member 69. The oil flowing from the oil cooler 70 is introduced into the
passage 67a via the upper hose 72. The return hose 73 is coupled to the
rearward pipe member 69. The oil flowing out of the passage 67a flows
downward into the motor unit 50 via the return hose 73. Since the
electric power control unit 60 is placed immediately above the motor unit
50, a loss caused by actuation of the oil pump 52 for feeding the oil
with a pressure to the cooler 66 is less.

[0078] Instead of placing the cooler 66 in the upper portion of the case
62 of the electric power control unit 60, for example, as shown in FIG.
7, the cooler 66 may be placed in a lower portion inside of a case 162 of
an electronic power control unit 160. In this construction, a loss caused
by actuation of the oil pump 52 for feeding the oil with a pressure to
the cooler 66 can be further lessened in the layout in which the electric
power control unit 160 is placed above the motor unit 50.

[0079] As can be seen from FIG. 6, the opening 62b of the case 62 of the
electric power control unit 60 closed by the casing 67 of the cooler 66
as described above has a smaller size than the substrate 61a of the power
module 61, and is formed in a portion of the substrate 61a, to be
precise, a portion corresponding to the power semiconductor chip 61b such
as an IGBT. That is, the cooler 66 is configured not to cool the entire
substrate 61a but to concentrically cool the power semiconductor chip 61b
which generates heat of a great amount. Because of this, a size of the
cooler 66 can reduced, and an amount of the oil flowing through the
cooler 66 can be reduced.

[0080] The power module 61 is accommodated into the case 62 such that the
substrate 61a is oriented upward. The cooler 66 to which the upper
surface of the substrate 61a is joined efficiently cools the power module
61. The heat radiated from the substrate 61a in a downward direction is
dispersed from the wall portion of the case 62. That is, the upper
portion of the case 62 joined to the floor portion 27 of the battery box
20 can be cooled by the cooler 66, while the lower portion of the case 62
can be efficiently cooled by the ram air. Because of this, the size of
the cooler 66 can be further reduced.

[0081] Other Embodiments

[0082] The above described embodiment is merely exemplary, and is in no
way intended to limit the present invention, its applications, and its
uses. For example, although in the present embodiment, the battery box 20
is placed to be inclined along the inclination of the main frame 8 of the
electric motorcycle 1 such that the floor portion 27 is directed downward
and obliquely forward, the present invention is not limited to this
layout. In addition, the battery box 20 need not be made of resin.

[0083] It is not necessary to mount the case 62 of the electric power
control unit 60 to the floor portion 27 of the battery box 20 as
described above. For example, the case 62 may be mounted to the rear wall
portion 26 of the battery box 20 from rearward. In this case, in view of
the fact that the oil is fed with a pressure from the motor unit 50, the
case 62 is preferably mounted to the battery box 20 in a location as low
as possible in the vicinity of the motor unit 50.

[0084] In that case, the structures described with reference to FIGS. 3,
4A and 4B are preferably employed. That is, the case 62 of the electric
power control unit 60 is preferably mounted in an inclined state such
that the upper wall portion 64 is joined to the rear wall portion 26 of
the battery box 20 from rearward. This allows the flat surface 64b of the
upper surface of the case 62 to be joined to the flat surface of the rear
wall portion 26 of the battery box 20.

[0085] In the present embodiment, the swelling portions 27b provided on
the floor portion 27 of the battery box 20 may be provided on the rear
wall portion 26 such that they swell in a forward direction (inward in
the battery box 20). And, the seat portions 64c of the upper wall portion
64 of the case 62 may be placed into the recesses 27c on the reverse side
of the swelling portions 27b from rearward.

[0086] The electric conductors connecting the electrodes 21 a of the
batteries 21 to the electrode terminals 63 of the electric power control
unit 60 inside of the battery box 20 are not limited to the bus bars 28
of the present embodiment. For example, electric wires may be provided to
extend in a range from the floor portion 27 of the battery box 20 to the
wall portions.

[0087] Although in the above embodiment, the electric motorcycle 1 has
been described, the electric vehicle of the present invention is not
limited to the motorcycle, but may be, for example, an ATV (all terrain
vehicle), a small truck, etc.

INDUSTRIAL APPLICABILITY

[0088] As described above, in the straddle-type electric vehicle of the
present invention, electric connecting work between the electric storage
device and the electric power control unit can be easily carried out, the
high-voltage lines can be minimized in length, and the high-voltage lines
are not exposed to outside. Therefore, the straddle-type electric vehicle
is very useful in the electric motorcycle.